Conventionally, an apparatus that prepares a machining program from a three-dimensional part shape is disclosed in, for example, Japanese Patent Application Laid-Open No. HEI 10-143222. This conventional technique is used to prepare a machining program that makes a machining center execute milling including a pocket machining portion and a hole machining portion. In other words, according to this conventional technique, first, a three-dimensional part shape including a pocket machining portion and a hole machining portion is input, and a machining region is extracted from the input part shape and material shape through three-dimensional shape processing. The extracted machining region is divided on a plane perpendicular to a Z axis, thereby to extract a pocket machining region and a point machining region, and prepare tool movement command data. According to this conventional technique, it is possible to prepare movement command data of a tool directly from the three-dimensional machined shape. Therefore, the machining program preparation work becomes extremely easy.
In order to obtain a part of a desired shape, in many cases, turning becomes necessary as well as milling. However, the conventional machining program preparation apparatus carries out only milling including a pocket machining portion and a hole machining portion, and does not carry out multi-machining including milling and turning. Therefore, in order to prepare a machining program for executing the multi-machining including milling and turning, an operator must divide the multi-machining into a turning step and a milling step while looking at the shape of the part. Consequently, the work becomes complicated, and the skill for accurately discriminating between the turning step and the milling step becomes necessary.
Therefore, the present invention has been achieved to solve the above problems. It is an object of the invention to provide an apparatus that can easily prepare a machining program for executing multi-machining including milling and turning.